University System of Maryland

Arie Kalkstein

Uri Tasch

The present invention provides an apparatus for controlling the angular positioning and stiffness modulations of a joint of a robotic manipulator by use of first and second motors and a control mechanisms. The first motor, preferably a direct current motor, controls angular positioning, while the second motor, preferably a servo motor, controls stiffness modulations. The angular positioning and stiffness modulations take place simultaneously, yet independently, thereby preventing interference. The first and second motors and the control mechanism are positioned within a housing. The control mechanism includes a shaft support member and threaded and non-threaded shafts. The threaded and non-threaded shafts extend from the first and second motors through threaded and non-threaded apertures, respectively, in the shaft support member to the housing where the threaded shaft is bearing mounted and the non-threaded shaft is supported in an aperture in the endwall of the housing to connect a pulley outside of the housing which is connected to a joint and link arrangement of a robotic manipulator. The shaft support member translates back and forth within the housing dependent on its position on the threaded shaft. When the shaft support member is nearer the housing endwall, the effective length of the shaft is short, the joint is stiff, effectively making the link stiff. When the shaft support member is nearer the shaft connection end of the motors, the effective length of the shaft is longer, the effective spring is soft, effectively making the actuator and link soft.

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Baltimore, MD, United States of America

Arie Kalkstein